Bisphenol A is commercially produced by the condensation reaction of acetone and two equivalents of phenol in the presence of a catalyst such as an ion-exchange resin. Bisphenol A is a high production volume compound with a world-wide estimated annual production of over 2 million tons. The demand for this compound is primarily due to its use as a monomer in the production of many high commodity materials such as epoxy resins and polycarbonates. Acetone, one of the precursors to bisphenol A, can be formed using the cumene process by reacting benzene and propylene. This reaction disadvantageously forms a methanol by-product that can result in a deactivation of the catalyst system used in the formation of bisphenol. This deactivation requires that the catalyst system be either regenerated or even completely replaced, resulting in production stoppages and additional expenditure in maintaining bisphenol A production facilities.
Separation of acetone-methanol mixtures is very difficult due to the formation of azeotrope at lower pressures. Processes addressing the problems associated with the azeotrope have been developed, including extractive distillation and pressure-swing azeotropic distillation. Separation of methanol from acetone can be achieved with the help of the above mentioned methods, however the separation is especially difficult in compositions initially comprising more than 80 weight percent of acetone due to a low relative volatility between the components at lower pressures. For example, reducing the concentration of methanol from 250 ppm to below 30 ppm conventionally require use of a heavy distillation column.
An improved method for the purification of acetone is therefore desirable.